Agree, TNT--hence many commercial regimens use a "crop nutrient profile" as a starting point for both synthetic and organic operations.
If the starting point is what you already have....and the goal is what you want (match the "plant's nutrient profile") then, imo, calculating the difference for each element is just part of the solution. Especially if you subscribe to the notion that: all organic sources of the same identical element/nutritient are not necessarily equal....and some combinations can exhibit synergistic characteristics, while some do not.
If the starting point is what you already have....and the goal is what you want (match the "plant's nutrient profile") then, imo, calculating the difference for each element is just part of the solution. Especially if you subscribe to the notion that: all organic sources of the same identical element/nutritient are not necessarily equal....and some combinations can exhibit synergistic characteristics, while some do not.